The LightSpin

Since January 2000 I have LightSpin dynamo, which was developted and produced from Dynosys AG in Switzerland. Actual the producer is Lightspin AG, Switherland. It was one of the first LighSpins of serial procuction. My experiences up to now I had written down on this page. As other LightSpin users, I had found some weak points which were removed in later versions. Since May 2003 there is a improved version, admitted for the use in Germany. Since November 2003 I am owner of one of these LightSpin. So it is time to write a complete new review.
Maybe actual models are different from my LightSpin.

What is the LightSpin?

The LightSpin is a side mounted dynamo, developed and built by the Swiss company Dynosys, actual from Lightspin AG. It seems to be the answer to the many biker's question: The manufacturer claims an efficiency of more than 80 %. Compared with this, usual side mounted dynamos have an efficiency of about 30 %.
The LightSpin is constructed as "magnetic circuit". The electrical output should fulfil the demands of German requirements. These are the stictest in Europe: At 5 km/h the output voltage has to be min. 3 V, at 15 km/h it has to be 5.7 V as a minimum. The maximum output voltage at 30 km/h is 7 V. The efficiency of usual dynamos is therefore limited: at about 6 km/h the output power is just 1.5 VA. The magnetic curcuit, which is realised in the LightSpin allows a higher efficiency with simultaneous compliance with the German requirements.
Dynosys tells a efficiency of generator and electronic system of 86 %. They tell also, that the biker has to give about 4.5 VA to get the output power of 3 VA. With a usual dynamo the biker has to give about 15 VA (efficience about 30 %). If you recalculate this, the efficiency of the LightSpin is about 67 %.
The technical data, according to the data sheet:
Output voltage at 10-50 km/h: 6,25 +/- 0,20 V
Output voltage at 50-65 km/h: 6,20 +/- 0,15 V
efficiency at 15 km/h: 75 %
efficiency at 30 km/h: 65 %
Maximum speed: 65 km/h

There were planned 3 versions of the LightSpin:

LightSpin safety version

(integrated standlight with NiMH accumulator): CHF 150.00

LightSpin

(upgradeble with standlight): CHF 110.00

LightSpin lite

(without standlight, no upgrade possible): CHF 90.00

Only the LightSpin lite is in production. Prices from 2000 plus postage and 16 % toll.

Experiences with the LightSpin

Former versions had the following weak points:

Slipping of the cap on the tyre when wet.
The problem was solved with a stronger spring resulting in a higher pressure of the dynamo to the tyre (actual 8,0/5,5 N, old version 6,5/4,0 N) and another form and material of the cap (another profile, harder). The diameter of the cap is slightly greater (actual: 26,5 mm, old 24,5 mm).

The dynamo switched on at vibrations.
The machanical parts were redesigned.

The electrical output did not fulfil the demands of German requirements.
Some modifications, perhaps of the electronics, solved the problem.

The new cap

This modifications are expected to reduce the efficiency of the actual version, compared with the version of the year 2000. More about the efficience is said later.

The LightSpin weights about 280 g (plus screws and mounting bracket, 53 g) and is more voluminous than other dynamos. The cables are connected with crimp connectors (2.8 mm) after unscrewing the base unit. The elctronics are well sealed under a plastic layer. It limits the output voltage and controls the loading of the accu of the other versions with standlight.
Turning the cap of the LightSpin shows the unusual: It turns and turns and turns! No other dynamo would do this.
Mounting the dynamo was easy, exact like any other side mounted dynamo. But the LightSpin is more voluminous, so mounting at the rear wheel can be interfere with the carrier.

For good performance Dynosys recommends an exactly adjustment of his axis to the center of the wheel. To make it easier, the dynamo has some marks on it's casing. The distance of the cap to the tyre should be 1.2 to 1.5 cm, when the dynamo is off. This hint is missing in the manual.

When a light with a Zener diode for limiting the voltage is used, this Zener diode has to be removed. It refuses the electronics, the diode might blow.

The LightSpin runs smooth under any conditions: rain, snow, slush, frost and temperatures down to -10 °C. For good performance Dynosys recommends a distance of the cap of 1.2 to 1.5 cm to the tyre, when the dynamo is off. My LightSpin actually is mounted with a distance of about 5 mm and there are no problems.

The Efficiency

Subjective the LightSpin has a very good efficiency. But is it only subjective? I gave my new LightSpin to Olaf Schultz and Andreas Oehler for some measurements.
Here the results from Andreas. The measurements were made with a Panaracer Pasela TourGuard 32-622 at 7 bar, the cap from the dynamo ran on the dynamo profile of the tyre, temparature 20°C, the dynamo exactly adjusted, distance of the cap to the tyre 8 mm, 5 minutes for running warm.
Measurements were made at 12 Ohm, this are 3 Watt output.

speed[km/h]

voltage[V]

effciency [%]

5

2,5

57,8

10

5,0

65,1

15

6,1

62,2

20

6,2

57,7

30

6,2

49,5

50

6,2

35,9

The efficiency is much lower than the from Dynosys mentioned values. Instead of 75 % at 15 km/h and 65 % at 30 km/h are not reached.
In the most interesting speed range of 15 up to 30 km/h the efficiency lowers from about 62 % to about 50 %.
Nevertheless the LightSpin is a very good dynamo. It is one of the best side mounted dynamo you can get. If you need more efficiency you have to choose the SON hub dynamo. But this is more expensive and you have to rebuild your front wheel.

More Light with the LightSpin

The data sheet from Oct. 2003 claims a maximum output power of 4.8 W. The lights according to German law will need 3.0 W only (2.4 W front and 0.6 W back). So there are 1.8 W "excess".
At the moment I use the LightSpin with two front lights (connected parallel), one with 3 W, the other with 2.4 W. In addition, there are two backlights (one for the bike, one for the trailer), needing each about 0.3 W. There is no switch for the backlight of the bike, but for the second front light (2.4 W).

Using just the 3-W-light, the dynamo has an output voltage of 6 Volt at about 13 km/h. Using both front lights, 6 V output was reached at about 17 km/h. So the maximum output power is 6 W or higher. Assuming an efficiency of 50 %, you have to give an power of 12 W. So it is a good idea to mount a switch for the second front light to use it only when you really need it. And don't forget to disable the Zener diodes (see above).
When it is raining, the cap beginns slipping on the tyre when riding more than 15 km/h.Caution: Dynosys clams 4,8 W maximum output power. Loading with 6 W seems to be possible for a short time. Maybe, the electronics will fail if you use a load of 6 W for longer time.